This invention relates to a method for the formation and manufacture of custom dentures from synthetic materials and includes a novel dental module for use therein.
The increasing longevity of individual life spans throughout much of the world accompanied by a heightened awareness of the need to maintain the ability to masticate a variety of foods throughout the individual's lifetime in order to provide for his nutritional, bulk and fiber needs has generated an expanding market for dentures. Over the years a host of different devices and a number of various methods of making them from synthetic materials have been utilized.
During the early portion of this century the use of plastic resins in denture devices was introduced. The resins were found to provide a more natural appearance than heretofore obtainable from prior materials. Also, materials of increased density and low porosity markedly reduced any health hazards associated with dentures. To this end, the denture industry after extensive testing and evaluation has adapted the plastic resin methyl methacrylate or, acrylic as it is commonly referred to, as the favored synthetic material for custom dentures. This material has remained the favored synthetic material for the fabrication of dentures to this date.
The characteristic of synthetic materials that enables them to be shaped and formed prior to the curing process which sets the material into a permanent form renders plastics or resins well suited for use in the dental laboratory. At present, conventional practice in the manufacture of individually tailored dentures begins with the dentist taking impressions of the oral cavity of the individual being fitted. A subsequent cast wax model is made in a dental laboratory to provide a working model for the technician.
The laboratory technician sets artificial teeth in both the upper and lower wax modules. At this time, both modules are usually mounted in a jig to allow review and adjustment of the occlusal aspects of the dentures. When the laboratory technician is satisfied as to the conformance of the module with the cast impression, the overall appearance of the denture and the provision of a satisfactory occlusal orientation of the teeth, the assemblage is then delivered to the dentist for custom fitting to the patient. After the fit is adjusted by the dentist, the wax model is returned to the laboratory for use in the preparation of an investment casting wherein dental stone or the like is placed around the wax model. The wax is melted to provide a cavity into which the acrylic is placed. After curing, the hardened or fixed denture is returned to the dentist whereupon the fit is again reviewed and often modified by the removal or addition of acrylic material.
The recipient's dentist then completes the fitting of his patient by trimming or adding material or modifying the size, shape and orientation of the denture to the individual's oral cavity. The dentist is working at this time with a fully cured synthetic material denture with mechanical techniques, such as grinding, to provide the details and adjustments necessary to provide a proper fit of the custom denture. This is an expensive and time consuming process requiring highly skilled personnel and thus is prohibitively expensive for the large portion of the population desirous of obtaining the benefits of denture devices.
To overcome the difficulties in trying to obtain custom dentures through the previously noted method, a combination of techniques have been employed. In one method, a fully cured module of synthetic material is made with the teeth permanently secured therein. Deformable backing or liner layers of uncured materials are provided against the cured material. The layered combination is then impression fitted in the patient's mouth for adjustment to the dimensions of the palatal vault. However, the fully cured module does not provide the dentist with the ability to modify the laterial spacing between the posterior teeth to accommodate different shapes and spacings for the endentulus ridge. Thus, only a partial customization is possible with this approach.
Other proposals for providing a custom denture device from a preformed module have included providing an embedded wire structure in an elastomeric environment as part of the cured denture device. The wire portion is deformed to simulate the approximate contours of the patient's palatal region. This approach is a compromise between fit and cost in that the denture can only be shaped to accommodate the large contours of the palatal vault and not the contours of the ridged portion of the oral cavity thus resulting in substantial discomfort to the user.
Accordingly, the present invention is directed to an uncured denture module formed to standard dimensions and which is capable of being conformed by the dentist to both the edentulus ridge and palatal areas of the oral cavity. The occlusal aspects of the dentures can be reviewed by the dentist prior to curing and the module then cured to permanently fix the teeth in the dentist's office. The invention provides a method of making custom dentures during a single visit to the dentist thereby reducing the costs thereof and the need for a series of steps performed at different locations.